Preparation and stabilization of nitroalkylperoxy nitrates

ABSTRACT

Vicinal nitroalkylperoxy nitrates are prepared and inhibited from thermally decomposing at temperatures of about 25* to 40* C. by continually contacting the nitrate with dinitrogen tetroxide.

United States Patent [191 Kablaoui et a].

[ PREPARATION AND STABILIZATION OF NITROALKYLPEROXY NITRATES [75] Inventors: Mahmoud S. Kablaoui, Wappingers Falls; Donald R. Lachowicz, Fishkill, both of NY.

[73] Assignee: Texaco, Inc., New York, NY.

[22] Filed: Apr. 24, 1972 [21] Appl. No.: 247,051

Related U.S. Application Data [63] Continuation of Ser. No. 71,673, Sept. -l4, 1970,

abandoned.

[52] U.S. Cl. 260/453 R, 260/398.5 [51] Int. Cl. C07c 77/02 [58] Field of Search 260/453 R, 398.5, 404.5

[ June 25, 1974 Primary Examiner-Glennon H. Hollrah Attorney, Agent, or Firm-T. H. Whaley; C. G. Reis 5 7 ABSTRACT Vicinal nitroalkylperoxy nitrates are prepared and inhibited from thermally decomposing at temperatures of about 25 to 40 C. by continually contacting the nitrate with dinitrogen tetroxide.

12 Claims, No Drawings PREPARATION-AND sTAifiL'rzATIoN or NITROALKYLPEROXY NITRATES BACKGROUND OF THE INVENTION nitrates. Further this invention relates to the nitrooxidation of olefins to nitroalkylperoxy nitrates at ambient temperatures and to the stabilization of the nitrates so formed.

Heretofore, nitroalkylperoxy nitrates were prepared at low temperatures ranging from about -40 to 20 C. as disclosed in US. Pat. No. 3,557,166. From the art it was taught that temperatures exceeding 20 C., whether encountered in the course of preparation or during subsequent storage adversely affected the nitrate product in that temperatures exceeding 20 C. facilitated decomposition of the nitroalkylperoxy nitrate to undesired products. The means previously employed to inhibit decomposition of the nitrate compound involved the extensive use of refrigeration equipment where the product was typically prepared and stored at temperatures of about C. Further, when the nitrate compound was contemplated for use as an intermediate in the preparation of other valuable products such as nitroolefins, nitroalcohols, dinitroalcohols, nitroketones or carboxylic acids, the nitrate so formed was immediately reacted leaving a minimal time for the material to thermally decompose at ambient conditions. From the standpoint of providing a commercially attractive process, the techniques heretofore employed left much to be desired in that economic penalties were encountered in view of the costly refrigeration required and the limited shelf life within which the product remained essentially free of by-products.

It is therefore an object of this invention to provide a method ?l."h i? PBJDELQEQWB9H1QH of nitroallrylperoxy nitrates.

It is another object of this invention to provide a method for stabilizing nitroperoxy nitrates which method can be performed in the absence of refrigeration equipment.

Yet another object of this invention is to provide a novel method for preparing nitroalkylperoxy nitrates at temperatures heretofore considered undesirable while simultaneously stabilizing or inhibiting thermal decomposition of the compound.

These and other objects of this invention will become apparent from a reading of the following detailed description and examples.

SUMMARY or TI-IE INVENTION Broadly, this invention contemplates a method of stabilizing a vicinal nitroalkylperoxy nitrate at temperatures of from about 25 to 40 C. which comprises contacting said nitrate with dinitrogen tetroxide wherein the mole ratio of said dinitrogen tetroxide to said nitrate is at least 0.01:1.

In another aspect of this invention there is contemplated a method of preparing and stabilizing a vicinal nitroalkylperoxy nitrate which comprises contacting an olefin with dinitrogen tetroxide and oxygen, said contacting undertaken at a temperature of from about 25 to 40 C. utilizing a mole ratio of olefin to dinitrogen tetroxide to oxygen of between about 1:l.01:1 and and R together r fifi form a polymethylene racficalof 121.5 z30 and throughout said contacting marntairiing a mole ratio of dinitrogen tetroxide to nitrate compounds so formed of at least about 0.01 1.

According to this invention, the contemplated vicinal nitroalkylperoxy nitrates are derived from olefins having at least 3 carbons of the formula:

where R is alkyl (saturated aliphatic hydrocarbon) containing from 1 to 18 carbons or polymethylenoic [(-CH2)1COOH where x is an integer of from 2 to 16], R is hydrogen, alkyl containing from 1 to 18 carbons or polymethylenoic as defined in R and where R from 3 to 22 carbons or a substituted polymethylene radical of 4 to 22 carbons. In preparing the nitrate, the olefin is simultaneously contacted with a mixture of dinitrogen tetroxide and oxygen to form a nitroalkylperoxy nitrate of the formula:

I H ooNo mmumwEA R-CI-ICI-IR1 where R and R a re heretofore defined. It will be appreciated that the nitro and peroxynitrato groups form on either olefinic carbon with the exception when the olefin group is terminal, the nitro group attaches itself to the terminal olefinic carbon. Therefore when R is other than hydrogen the product is actually a mixture of compounds.

I In one embodiment of this invention, the aforementioned nitroalkylperoxy nitrates are prepared at temperatures ranging from about 25 to 40 C. and preferably from 25 to 30 C. The instant method involving operating about or above ambient temperatures provides a viable approach and obviates the necessity to employ ibetisiverrfigeriitiim"e ui ment. To successfully operate at these higher temperatures, i.e., 25 to 40 C., so as to inhibit thermal decomposition of the nitroperoxy nitrate formed by contacting an olefin, dinitrogen tetroxide and oxygen, it has been found that such contacting must be uridertalreii utilizing a mole ratio of olefin to dinitrogen tetroxide of at least about 1:1.01 to about 1:15, preferably 111.05 to 1:1.1, and maintaining a mole ratio of dinitrogen tetroxide to nitrate compound formed of at least 0.01:1 to 01:1,

preferably 0.03il to 0.06:1. The combinatio riof reaction temperature and the mole ratio of dinitrogen tetroxide to olefin is critical if thermal decomposition ofthe nitrat' sISTJr mEElTsfoTeiifiiibited. It has been" found that the amount of dinitrogen tetroxide specified above and present during the course of the reaction acts as a stabilizer so as to deter decomposition of the nitrooxidation reaction product. In the absence of the aforementioned levels of dinitrogen tetroxide,

gen another N02 group forms rather than the desired peroxy compound. In general, therefore, the reactant mole ratio of olefin to dinitrogen tetroxide to oxygen is maintained at the ratios specified above. As an additional benefi tderived rro'ifi employing the higher conversion temperatures, the reaction time is generally reduced to between one-quarter to one-half the time previously employed.

Interaction between the aforementioned components can be promoted by agitation and, if desired, by introducing art inert liquid diluent suitably having a boiling point of between about 30 to 100 C. such as n-hexane, n-heptane, benzene, carbon tetrachloride and diethylether. Preferably, a diluent boiling within the ope rative react ion temperature range of 25 to 40 C. is employed such as n-pentane, petroleum ether or diethylether which permits control over the reaction temperature by operating at the diluent reflux temperature. When diluents possessing boiling points beyond 40 C. are employed control over the reaction temperature can be exercised by water circulating coils so as to remove heat from the reaction.

The formed nitroperoxy nitrate maintained at a temperature of about 25 to 40 C. is thereafter recovered by standard means as for example stripping of the volatiles. Immediately upon recovery, the "p oduct is stabilized for storage by contacting with from at least 0.0l to about 0fl moles of dinitrogen tetroxide per mole of nitroalkylperoxy nitrate. In the absence of dinitrogen tetroxide, storage of the nitrate compound at ambient temperatures of 25 to 40 C. is not feasible and decomposition to the nitronitrate, nitroalcohol and nitroketone occurs. By maintaining the nitroperoxy nitrate in the presence of the above ratio of dinitrogen tetroxide, the compound can be stored for extended periods of time, a; rara'am ie a t lea st 24hoursand longer.

It is to be noted that the nitrating agent denitrogen tetroxide is actually an equilibrium mixture of dinitrogen te t roxide ahdnitrogen dioxide with the equilibrium being driven to essentially 100 percent dinitrogen tetroxide at 0 C. and essentially 100 percent nitrogen dioxide at 140 C. Under advantageous conditions the nitrating agent is normally introduced into the reaction system at the rate of between about 0.02 and 0.2 gram/minute/ gram of olefin.

The oxygen employed in the instant invention may be in pure form or diluted with air or in admixture with a an inert gases such as nitrogen or argon. Under advantageous conditions the oxygen is introduced into the reaction system at the rate of between about 80 and 120 milliliters/minute/gram of olefin.

Pursuant to this invention the contemplated nitro peroxynitrates are derived from olefins corresponding to the aforementioned formula and illustrated by propylene, l-butene, 2-pentene, 3-hexene, l-octene, Z-dodecene, 4-tetradecene, l-hexadecene, 7-heptadecene and l-eicosene. Cyclic olefins contemplated herein are illustrated by cyclopentene, 3-methylcyclopentene, cyclohexene. cyclooctene. cyclododecene, cy-' clooctadecene and cyclodocosene. Mixtures of olefins such as 3-decene and 4-decene, 4-dodecene, and 5-do decene, mixtures of internal tetradecenes or mixtures of C to C or C to C olefins, mixtures of cycloolefins such as 3-methylcyclohexene, 4-methylcyclo hexene and cycloheptene or cyclohexene, methylcyclohexene, ethylcyclohexene, methyl ethylcyclohex ene and trimethylcyclohexene are similarly contemplated.

Examples of the nitroalkylperoxy nitrate products formed by the instant method are l-ni t r o- TZ-dodecylperoxy nitrate, l-nitro-2-octylperoxy nitrate, l-nitro- 2-octadecylperoxy nitrate, 1-nitro-2-hexylperoxy nitrate, mixtures of 5-nitro-4-tridecylperoxy nitrate and 4-nitro-5-tridecylperoxy nitrate and mixtures of 11- nitro-lO-eicosylperoxy nitrate and l0-nitro-l l-eicosylperoxy nitrate, l-nitro-2-cyclohexylperoxy nitrate and l-nitro-2-cyclododecylperoxy nitrate.

The nitroperoxy nitrates so prepared are useful as intermediates in the preparation of other valuable products as nitroolefins, nitroalcohols, dinitroalcohols, nitroketones, amines and carboxylic acids.

In order to more fully illustrate the nature of our invention and manner of practicing the same the following examples are presented.

EXAMPLE I Into a 300 milliliter flask equipped with a thermometer, gas inlet and condenser, there was charged 22.4 grams (0.10 mole) of l-hexadecene and 150 milliliters of carbon tetrachloride. Dinitrogen tetroxide (9.8 grams, 0.106 mole) and oxygen at the rate of milliliters per minute were introduced to thereactor over a period of two hours and the reaction conducted at'a temperature of from 25 to 30 C. The ratios of the materials charged were in accordinace with the instant invention. The volatiles including the inert diluent medium in the reaction mixture were removed by vacuum distillation and the residual product comprised 34.0 grams of l-nitro-2-hexadecylperoxy nitrate identified by infrared and nuclear magnetic resonance spectroscopy.

' EXAMPLE II i A portion ofthe rbdiid'bi Example ITn a m ely 3.5

EXAMPLE Ill Example II was repeated except that dinitrogen tetroxide was not added. At'ter4 hours at 25 to 35C it was determined after examination that the nitmpcr oxy nitrate had entirely decomposed to l-nitro-Z- hexadecanone, l-nitro-2-hexadecylnitrate and l-nitro- 2hexadecanol in the ratio of 4:3:3 respectively.

EXAMPLE IV To the apparatus of Example I. there was charged 22.4 grams (0.1 mole) of l-hexadecene and milliliters of carbon tetrachloride. Dinitrogen tetroxide. (9.0 grams, 0.098 mole) and oxygen at the rate of 90 milliliters per minute were introduced and the reaction conducted as in Example 1. Analysis of the product indicated the presence of 30 to 45 percent decomposed nitroperoxy nitrate as the reaction temperature wherein said nitrate has the formula:

increased from 25 to 30' C. The by-produc ts were the same as those obtained in Example 11 except in greater amount.

EXAMPLE V The product of Example IV was stored at 25 to 35 C. for 4 hours. Re-examination and analysis of the product indicated the"ass'encaafniwaaaaxy'ituate; Only the lay-products l-nitro-Z-hexadecanone, l-nitro- 2-hexadecylnitrate' and l-nitro-2-hexadecanol were detected.

EXAMPLE V1 Employing the apparatus and procedure of Example 1, there was charged 33.6 grams (0.20 mole) of T. ln a method ofstabilizing vicinal nitroalkylperoxy nitrate at temperatures of from about 25 to 40 C.

where R is alkyl containing from 1 to 18 carbons or (CH -).r COOH where x is an integer of from 2 to 16, R is hydrogen, alkyl containing from 1 to 18 carbons or (-C z OOH where x is heretofore defined or where R and R together form a polymethlyene radical of from 3 to 22 carbons or a lower alkyl substituted polymethylene radical of 4 to 2 2 carbons the improvement which comprises contacting said nitrate with dinitrogen tetroxide wherein the mole ratio of said dinitrogen tetroxide to said nitrate is 0.01:1 to 0.121.

2. A method according to claim 1 wherein the mole ratio of dinitrogen tetroxide to said nitrate is 0.03:1 to 0.06:1.

3. A method according to claim 1 wherein said nitrate is 1nitro-2-hexadecylperoxy nitrate.

4. A method according to claim 1 wherein said nitrate is 1 iYitro-Z-cyclododecylperoxy nitrate.

5. A method of preparing and stabilizing a vicinal nitroalkylperoxy nitrate which comprises:

(a) contacting an olefin with dinitrogen tetroxide and oxygen, wherein said olefin has the formula:

where R is alkyl containing from 1 to 18 carbons or (CH ),COOH where x is an integer of from 2 to 16, R is liydrogen. aikyl containing from I to 18 carbons or (-CH ),COOH where x is as heretofore defined or where'R and R together form a polymethylene radical of from 3 to 22 carbons or a lower alkyl substituted polymethylene radical of 4 to 22 carbons, said contacting undertaken at a temperature of from 25 to 40 C. utilizing a mole ratio of olefin to dinitrogen tetroxide to oxygen of between about 1:1.01:1

and 121.5130 thereby forming a vicinal nitroalkylperoxy nitrate of the formula:

OONO2 where R and R are as heretofore defined, and (b) contacting said nitrate formed in (a) with dinitrogen tetroxide, the mole ratio of said dinitrogen tetroxide to said nitrate being 0.01 :1 to 01:1.

6. A method according to claim 5 wherein said contacting in (a) is conducted at 25 to 30 C.

7. A method according to claim 5 wherein the mole ratio of dinitrogen tetroxide to said nitrate in (b) is 0.03:1 to 0.06:1.

8. A method according to claim 5 wherein the mole ratio of olefin to dinitrogen tetroxide to oxygen in (a) is from 1:1.05:1 to 1:1. 1:30.

9. A method according to claim 5 wherein said contacting in (a) is undertaken in the presence of inert liquid diluent having a boiling point of between about 30 to C.

T0. A method according to claim s wherein said can tacting in (a) is conducted in the presence of an inert liquid diluent selected from group consisting of n-penfa ne,' ptroTeiIrii "Elmer. diefliflethr and carbon tetrachloride.

11. A method according to cliam 5 wherein said nitrate is 1-nitro-2-hexadecylperoxy nitrate. wmm

12. A methodaccord ingto claim 5 wherein said nitrate is l-nitro-2-cyclododecylperoxy nitrate. 

2. A method according to claim 1 wherein the mole ratio of dinitrogen tetroxide to said nitrate is 0.03:1 to 0.06:1.
 3. A method according to claim 1 wherein said nitrate is 1-nitro-2-hexadecylperoxy nitrate.
 4. A method according to claim 1 wherein said nitrate is 1-nitro-2-cyclododecylperoxy nitrate.
 5. A method of preparing and stabilizing a vicinal nitroalkylperoxy nitrate which comprises: a. contacting an olefin with dinitrogen tetroxide and oxygen, wherein said olefin has the formula: R - CH CH - R1 where R is alkyl containing from 1 to 18 carbons or (-CH2-)xCOOH where x is an integer of from 2 to 16, R1 is hydrogen, alkyl containing from 1 to 18 carbons or (-CH2-)xCOOH where x is as heretofore defined or where R and R1 together form a polymethylene radical of from 3 to 22 carbons or a lower alkyl substituted polymethylene radical of 4 to 22 carbons, said contacting undertaken at a temperature of from 25* to 40* C. utilizing a mole ratio of olefin to dinitrogen tetroxide to oxygen of between about 1:1.01:1 and 1:1.5:30 thereby forming a vicinal nitroalkylperoxy nitrate of the formula:
 6. A method according to claim 5 wherein said contacting in a is conducted at 25* to 30* C.
 7. A method according to claim 5 wherein the mole ratio of dinitrogen tetroxide to said nitrate in b is 0.03:1 to 0.06:1.
 8. A method according to claim 5 wherein the mole ratio of olefin to dinitrogen tetroxide to oxygen in a is from 1:1.05:1 to 1:1.1:30.
 9. A method according to claim 5 wherein said contacting in a is undertaken in the presence of inert liquid diluent having a boiling point of between about 30* to 100*C.
 10. A method according to claim 5 wherein said contacting in a is conducted in the presence of an inert liquid diluent selected from group consisting of n-pentane, petroleum ether, diethylether and carbon tetrachloride.
 11. A method according to claim 5 wherein said nitrate is 1-nitro-2-hexadecylperoxy nitrate.
 12. A method according to claim 5 wherein said nitrate is 1-nitro-2-cyclododecylperoxy nitrate. 